FEAR OF CIVIL WAR GROWS IN LEBANON

By IHSAN A. HIJAZI, Special to the New York Times

Published: September 24, 1988

BEIRUT, Lebanon, Sept. 23—
With the Presidency vacant, a Christian-led Cabinet and a Moslem-led Cabinet each claimed to be the legitimate government of Lebanon today.

The developments raised fears that open civil war would resume, as Moslem leaders warned that Lebanon had been brought close to a formal partition into Christian and Moslem states.

Parliament, which has been unable to agree on a presidential candidate, canceled a session that was to have sought an end to the deadlock today. No new date was set. The quest for a new president has been deadlocked over the need to find a candidate acceptable to both the Christian leadership and to Syria, which is allied with a number of Moslem factions and has played an influential role as power broker in Lebanon since Israeli troops began withdrawing after their 1982 invasion. General Heads Cabinet

Just minutes before his six-year term expired at midnight, President Amin Gemayel announced the formation of an interim military Government whose announced intent would be to govern until the election of a new President. Its leader, as Prime Minister, is the Christian commander of the army, Maj. Gen. Michel Aoun. Mr. Gemayel also included three Moslem officers as members of the six-man military Cabinet, but they declined to take part.

Moslem and leftist leaders aligned with Syria immediately condemned Mr. Gemayel's move as a step toward the formal partition of Lebanon, and made it clear that they continued to support the existing Cabinet, which is headed by a Sunni Moslem, Selim al-Hoss.

Since Lebanon achieved independence in 1943, its presidents have been Christians and its Cabinets have been led by Moslems, under an unwritten covenant designed to let the country's various religious groups share power.

For two and a half years, the Government has been virtually paralyzed by political divisions between the Christians leaders, who are resisting the growth of Syrian influence here, and Moslems backed by Syria. Nevertheless, the country has been relatively calm under cease-fire arrangements enforced in large part by the presence in Lebanon of 25,000 Syrian troops.

The principal new fear stirred by the crisis over the presidency is that the presence of two competing governments will eliminate all pretense of national unity and lead to a resumption of full-scale civil war. A Career Officer

General Aoun, a 53-year-old career officer, moved into the Presidential Palace in the Christian suburb of Baabda today, after Mr. Gemayel left the building. A whole wing in the palace, which is not far from the general's own military headquarters, has been transformed into an office for the new Prime Minister.

Almost simultaneously, Dr. Hoss, a 59-year-old economist educated in the United States, went to the Prime Minister's building in West Beirut, the predominantly Moslem half of the capital, for a meeting with Arab and other foreign diplomats.

He announced that he considered his Cabinet to be Lebanon's only legitimate authority, and summoned his ministers to a meeting Saturday at his office. [ Daniel Simpson, the ranking American diplomat in Lebanon, visited Mr. Hoss in West Beirut and told reporters later that ''it was an opportunity to be informed of the situation as it stands'' but did not say which government the United States would recognize, The Associated Press reported. The news service said that Christian gunmen stopped Mr. Simpson's car as it was crossing back into East Beirut from West Beirut and tried to stop him from returning to his residence, but that he later was driven home safely on roads controlled by units of the regular army. ] Called Violation of Covenant Dr. Hoss released a message to Patriarch Nasrallah Sfair, the most senior Christian prelate, in which he said the appointment of a Cabinet under a Christian violated the unwritten national covenant.

The pact gave the office of Prime Minister to the Sunni Moslems and that of Speaker of Parliament to the Shiite Moslems, while the Christians were assigned the posts of President and commander of the army.

Dr. Hoss also said the new Cabinet could not function with three of its members refusing to join.

Mr. Gemayel handed over power to the army commander after Parliament failed twice in the last five weeks to meet to elect a successor. The 76 Moslem and Christian deputies were unable to agree on a consensus candidate.

One reason behind the fear that renewed fighting will break out is that the Cabinet headed by Dr. Hoss is regarded as a cease-fire administration.

It was formed at the end of April 1984, after the Moslem side agreed to a halt in hostilities with the Christians.

A few months before, the balance of power had been tipped against the Christians when Israeli troops, which had invaded Lebanon in 1982 and had been allied with the Christians, pulled out of West Beirut and the Shuf district.

After that, Moslem militiamen backed by Syria drove units of the army loyal to President Gemayel out of West Beirut, and Druse warriors routed Christian militiamen in the Shuf mountains southeast of the capital.

Only a firm stand by an army brigade, then commanded by General Aoun, stopped Moslem fighters from overruning the Baabda palace. A Boycott by the Moslems

When the Cabinet was appointed that spring, its mission was to strive for national unity and introduce political change. General Aoun was chosen to command the army as part of that Moslem-Christian understanding.

But hopes for unity became extremely dim two and a half years ago, when Moslem officials began a boycott of Mr. Gemayel after he torpedoed a Syrian-sponsored pact that had been offered as a formula for ending the civil war. He and his Christian supporters said the pact would erode the Christian share in power in favor of the Moslems and insure a permanent Syrian presence in Lebanon. The Christians want the Syrian troops withdrawn.

The Cabinet situation was further complicated after the Prime Minister, Rashid Karami, was assassinated in June 1987 in a bomb explosion aboard a military helicopter in which he was traveling. After that, President Gemayel kept the Cabinet in a caretaker capacity and named Dr. Hoss Acting Prime Minister.

While the politicians were locked in their conflict here, Israeli air force jets struck at Palestinian guerrilla bases in southern Lebanon.

Police and witnesses said the planes rocketed two bases belonging to Al Fatah, the mainstream movement led by Yasir Arafat, the chairman of the Palestine Liberation Organization, and a third operated by the Democratic Front for the Liberation of Palestine, a Marxist group, in the Mieh Mieh district at the southern edge of Sidon, 25 miles south of Beirut.